Question 1

The sum of the deviations around the mean is:

Accepted Answer

A) greater than zero if data are right-skewed. 
B) smaller when the units are smaller (e.g., milligrams versus kilograms). 
C) always zero. 
D) dependent on the sample size. 
A) greater than zero if data are right-skewed. 
B) smaller when the units are smaller (e.g., milligrams versus kilograms). 
C) always zero. 
D) dependent on the sample size.

Question 2

Which of the following is not a valid description of an outlier?

Accepted Answer

A) A data value beyond the outer fences 
B) A data value that is very unusual 
C) A data value that lies below Q1 or above Q3 
D) A data value several standard deviations from the mean. 
A) A data value beyond the outer fences 
B) A data value that is very unusual 
C) A data value that lies below Q1 or above Q3 
D) A data value several standard deviations from the mean.

Question 3

In the following data set {7, 5, 0, 2, 7, 15, 5, 2, 7, 18, 7, 3, 0}, the value 7 is:

Accepted Answer

A) the mean. 
B) the mode. 
C) both the mode and median. 
D) both the mean and mode. 
A) the mean. 
B) the mode. 
C) both the mode and median. 
D) both the mean and mode.

Question 4

A smooth distribution with one mode is negatively skewed (skewed to the left). The median of the distribution is $65. Which of the following is a reasonable value for the distribution mean?

Accepted Answer

A) $76 
B) $54 
C) $81 
D) $65 
A) $76 
B) $54 
C) $81 
D) $65

Question 5

Given the data set 2, 5, 10, 6, 3, the median value is 3.

Accepted Answer

A) True 
 B)False

Question 6

Twelve students were asked how many credit cards they owned. The responses were 0, 0, 1, 2, 2, 3, 3, 4, 4, 5, 5, 11. (a) Find the mean, median, and mode. (b) Which measure of center seems best in this case? (c) Find the first and third quartiles. What do they tell you?

Accepted Answer

(a) Mean is 3.33, median is 3, mode is n

Question 7

Histograms are best used to:

Accepted Answer

A) provide a visual estimate of the standard deviation. 
B) show the quartiles of the data set. 
C) assess the shape of the distribution. 
D) reveal the interquartile range of the data set. 
A) provide a visual estimate of the standard deviation. 
B) show the quartiles of the data set. 
C) assess the shape of the distribution. 
D) reveal the interquartile range of the data set.

Question 8

Twelve randomly chosen students were asked how many times they had missed class during a certain semester, with this result: 2, 1, 5, 1, 1, 3, 4, 3, 1, 1, 5, 18. For this sample, the median is:

Accepted Answer

A) 2. 
B) 3. 
C) 3.5. 
D) 2.5. 
A) 2. 
B) 3. 
C) 3.5. 
D) 2.5.

Question 9

Which is not true of an outlier?

Accepted Answer

A) It is likely to be from a different population. 
B) It suggests an error in recording the data. 
C) It is best discarded to get a better mean. 
D) It is an anomaly that may tell the researcher something. 
A) It is likely to be from a different population. 
B) It suggests an error in recording the data. 
C) It is best discarded to get a better mean. 
D) It is an anomaly that may tell the researcher something.

Question 10

Which is a characteristic of the mean as a measure of center?

Accepted Answer

A) Deviations do not sum to zero when there are extreme values. 
B) It is less reliable than the mode when the data are continuous. 
C) It utilizes all the information in a sample. 
D) It is usually equal to the median in business data. 
A) Deviations do not sum to zero when there are extreme values. 
B) It is less reliable than the mode when the data are continuous. 
C) It utilizes all the information in a sample. 
D) It is usually equal to the median in business data.

Question 11

If samples are from a normal distribution with μ = 100 and σ = 10, we expect:

Accepted Answer

A) about 68 percent of the data within 90 to 110. 
B) almost all the data within 80 to 120. 
C) about 95 percent of the data within 70 to 130. 
D) about half the data to exceed 75. 
A) about 68 percent of the data within 90 to 110. 
B) almost all the data within 80 to 120. 
C) about 95 percent of the data within 70 to 130. 
D) about half the data to exceed 75.

Question 12

Which of the following statements is likely to be true?

Accepted Answer

A) The median personal income of California taxpayers would probably be near the mean. 
B) The interquartile range offers a measure of income inequality among California residents. 
C) For income, the sum of squared deviations about the mean is negative about half the time. 
D) For personal incomes in California, outliers in either tail would be equally likely. 
A) The median personal income of California taxpayers would probably be near the mean. 
B) The interquartile range offers a measure of income inequality among California residents. 
C) For income, the sum of squared deviations about the mean is negative about half the time. 
D) For personal incomes in California, outliers in either tail would be equally likely.

Question 13

Find the coefficient of variation of these numbers: 14, 17, 17, 19, 26. Would the variability of those numbers be greater than, less than, or the same as the variability of 24, 27, 27, 29, 36? Defend your answer.

Accepted Answer

Relative variation i

Question 14

If the mean and median of a population are the same, then its distribution is:

Accepted Answer

A) normal. 
B) skewed. 
C) symmetric. 
D) uniform. 
A) normal. 
B) skewed. 
C) symmetric. 
D) uniform.

Question 15

Craig operates a part-time snow-plowing business using a 2002 GMC 2500 HD extended cab short box truck. This box plot of Craig's MPG on 195 tanks of gas does not support which statement?

Accepted Answer

A) There are several outliers. 
B) This is a very right-skewed distribution. 
C) Most MPG values are concentrated in a narrow range. 
D) The interquartile range is less than 2 MPG. 
A) There are several outliers. 
B) This is a very right-skewed distribution. 
C) Most MPG values are concentrated in a narrow range. 
D) The interquartile range is less than 2 MPG.

Question 16

Bob's sample of freshman GPAs showed a mean of 2.72 with a standard deviation of 0.31. (a) What range would you predict for all the grades? For the middle 95 percent? Explain. (b) Why might your estimates be inaccurate?
E.R. is based on the normal distribution, so could be inaccurate if grades are skewed.

Accepted Answer

By the Empirical Rule, we expect the mid

Question 17

For U.S. adult males, the mean height is 178 cm with a standard deviation of 8 cm and the mean weight is 84 kg with a standard deviation of 8 kg. Elmer is 170 cm tall and weighs 70 kg. It is most nearly correct to say that:

Accepted Answer

A) Elmer's weight is more unusual than his height. 
B) Elmer is heavier than he is tall. 
C) Height and weight have the same degree of variation. 
D) Height has more variation than weight. 
A) Elmer's weight is more unusual than his height. 
B) Elmer is heavier than he is tall. 
C) Height and weight have the same degree of variation. 
D) Height has more variation than weight.

Question 18

A leptokurtic distribution is more sharply peaked (i.e., thinner tails) than a normal distribution.

Accepted Answer

A) True 
 B)False

Question 19

Briefly describe this sample of departure delays on American Airlines flights out of Denver over a seven-day period, March 3-9 (n = 149 flights).

Accepted Answer

Short left whisker, skewed rig

Question 20

Chebyshev's Theorem says that at most 50 percent of the data lie within 2 standard deviations of the mean.

Accepted Answer

A) True 
 B)False

The sum of the deviations around the mean is:

Which of the following is not a valid description of an outlier?

In the following data set {7, 5, 0, 2, 7, 15, 5, 2, 7, 18, 7, 3, 0}, the value 7 is:

A smooth distribution with one mode is negatively skewed (skewed to the left). The median of the distribution is $65. Which of the following is a reasonable value for the distribution mean?

Given the data set 2, 5, 10, 6, 3, the median value is 3.

Twelve students were asked how many credit cards they owned. The responses were 0, 0, 1, 2, 2, 3, 3, 4, 4, 5, 5, 11. (a) Find the mean, median, and mode. (b) Which measure of center seems best in this case? (c) Find the first and third quartiles. What do they tell you?

Histograms are best used to:

Twelve randomly chosen students were asked how many times they had missed class during a certain semester, with this result: 2, 1, 5, 1, 1, 3, 4, 3, 1, 1, 5, 18. For this sample, the median is:

Which is not true of an outlier?

Which is a characteristic of the mean as a measure of center?

If samples are from a normal distribution with μ = 100 and σ = 10, we expect:

Which of the following statements is likely to be true?

Find the coefficient of variation of these numbers: 14, 17, 17, 19, 26. Would the variability of those numbers be greater than, less than, or the same as the variability of 24, 27, 27, 29, 36? Defend your answer.

If the mean and median of a population are the same, then its distribution is:

Craig operates a part-time snow-plowing business using a 2002 GMC 2500 HD extended cab short box truck. This box plot of Craig's MPG on 195 tanks of gas does not support which statement?

For U.S. adult males, the mean height is 178 cm with a standard deviation of 8 cm and the mean weight is 84 kg with a standard deviation of 8 kg. Elmer is 170 cm tall and weighs 70 kg. It is most nearly correct to say that:

A leptokurtic distribution is more sharply peaked (i.e., thinner tails) than a normal distribution.

Briefly describe this sample of departure delays on American Airlines flights out of Denver over a seven-day period, March 3-9 (n = 149 flights).

Chebyshev's Theorem says that at most 50 percent of the data lie within 2 standard deviations of the mean.

Overview of Statistics

Data Collection

Describing Data Visually

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

Exam 4: Descriptive Statistics

The sum of the deviations around the mean is:

Which of the following is not a valid description of an outlier?

In the following data set {7, 5, 0, 2, 7, 15, 5, 2, 7, 18, 7, 3, 0}, the value 7 is:

A smooth distribution with one mode is negatively skewed (skewed to the left). The median of the distribution is $65. Which of the following is a reasonable value for the distribution mean?

Given the data set 2, 5, 10, 6, 3, the median value is 3.

Twelve students were asked how many credit cards they owned. The responses were 0, 0, 1, 2, 2, 3, 3, 4, 4, 5, 5, 11. (a) Find the mean, median, and mode. (b) Which measure of center seems best in this case? (c) Find the first and third quartiles. What do they tell you?

Histograms are best used to:

Twelve randomly chosen students were asked how many times they had missed class during a certain semester, with this result: 2, 1, 5, 1, 1, 3, 4, 3, 1, 1, 5, 18. For this sample, the median is:

Which is not true of an outlier?

Which is a characteristic of the mean as a measure of center?

If samples are from a normal distribution with μ = 100 and σ = 10, we expect:

Which of the following statements is likely to be true?

Find the coefficient of variation of these numbers: 14, 17, 17, 19, 26. Would the variability of those numbers be greater than, less than, or the same as the variability of 24, 27, 27, 29, 36? Defend your answer.

If the mean and median of a population are the same, then its distribution is:

Craig operates a part-time snow-plowing business using a 2002 GMC 2500 HD extended cab short box truck. This box plot of Craig's MPG on 195 tanks of gas does not support which statement?

For U.S. adult males, the mean height is 178 cm with a standard deviation of 8 cm and the mean weight is 84 kg with a standard deviation of 8 kg. Elmer is 170 cm tall and weighs 70 kg. It is most nearly correct to say that:

A leptokurtic distribution is more sharply peaked (i.e., thinner tails) than a normal distribution.

Briefly describe this sample of departure delays on American Airlines flights out of Denver over a seven-day period, March 3-9 (n = 149 flights).

Chebyshev's Theorem says that at most 50 percent of the data lie within 2 standard deviations of the mean.

Overview of Statistics

Data Collection

Describing Data Visually

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters